Borrowdale graphite.
The mine at Borrowdale was the first, and for a century the only, source of graphite, making it critical to the world's supply of pencils in the 1700s.Source:Andrew GoodallContributor:Andrew GoodallAcquired:2 April, 2009Text Updated:3 April, 2009Price: DonatedSize: 2"Purity: >95%